The present invention is directed generally to infusion systems, and more particularly to an implantable fill port having an internal needle-actuated safety valve for introducing medicament to a subcutaneous reservoir.
Implanted manually-actuated micro-infusion pump systems are advantageously employed when specific dosages of a medicament are to be administered within the human body at various times over an extended time period, as in the treatment of diabetes and other diseases of the digestive system.
In the treatment of diabetes a dispensing system comprising a combined pump and medicament reservoir system is subcutaneously implanted in soft tissue close to the delivery site, such as over the peritoneum and abdominal muscles, and a catheter is utilized to deliver insulin to the site. Alternatively, the reservoir is implanted remotely from the site and connected to a pump system by means of a flexible catheter. When insulin is required actuation of the pump system is accomplished by the patient applying pressure on the skin surface overlying the pump.
Typically, medicament is added to the reservoir at periodic intervals through a fill port provided in the wall of the reservoir. A hypodermic needle is inserted through the skin so as to contact and puncture a needle, penetrable fluid impermeable membrane included in the port. All remaining medicament is then withdrawn, and a new known volume of medicament is introduced through the needle.
One drawback of previous implantable fill ports was their susceptibility to leakage when fluid in the associated reservoir was subjected to an applied pressure. This problem became more pronounced with repeated use of the fill port, since repeated puncturing of the fill port septum by the hypodermic needle weakened or decreased the effectiveness of the sealing membrane.
The present invention overcomes this problem by incorporating within the fill port an integral needle-actuated valve. Upon introduction of the needle through the septum of the port the valve is automatically opened to allow the addition or withdrawal of the medicament. Upon removal of the needle the valve automatically closes, and by reason of the construction of the valve increased pressure within the reservoir enhances the sealing properties of the valve. Also, in accordance with another aspect of the invention, the septum may be maintained under compression to preclude leakage through the septum upon removal of the needle.
Accordingly, it is a general object of the present invention to provide a new and improved fill port for implantable dispensing systems.
It is a more specific object of the present invention to provide a new and improved fill port which is less susceptible to leakage from internally applied medicament pressure.
It is a more specific object of the present invention to provide a new and improved implantable fill port which opens upon introduction of a needle, and is automatically closed upon removal of the needle.